Incus is not a replacement for lxc. It's an alternative for LXD (LXD project is still active). Both Incus and LXD are built upon liblxc (the library version of lxc) and provide a higher level user interface than lxc (eg: projects, cloud-init support, etc). However, lxc gives you fine grained control over container options (this is sort of like flatpak and bubblewrap).

So, if you don't need the fine grained control of lxc, Incus may be a more ergonomic solution.

PS: Confusingly enough, LXD's CLI is also named lxc.